Dye laser

ABSTRACT

There is herein, disclosed a dye laser including a container for a dye solution and a pumping energy source coupled thereto, said dye solution containing a perimidone dye formula (I): ##STR1## wherein R 1  is a hydrogen atom, an alkyl group, a trifluoromethyl group, an alkoxycarbonyl group, an alkoxycarbonylalkyl group, an aralkyl group or a phenyl group; R 2  is an optionally substituted alkoxycarbonyl group, a cyclohexyloxycarbonyl group, tetrahydrofurfuryloxycarbonyl group, an aryloxycarbonyl group, a benzyloxycarbonyl group, an acyl group, a cyano group or an optionally substituted carbamoyl group; R 3  and R 4  which may be the same or different are each a hydrogen atom, an alkyl group, an alkoxyalkyl group, an aralkyl group or an aryl group.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a dye laser, and more particularly, toa dye laser that uses a perimidone dye as the active medium and emitslaser light having an oscillation wavelength of 500 to 550 nm.

2. Description of the Prior Art

While many organic dyes have been proposed for use as active media inlasers, the use of perimidone dyes for emitting laser light having anoscillation wavelength of 500 to 550 nm has not been suggested.

SUMMARY OF THE INVENTION

One object of the present invention is to provide a novel perimidone dyefor use as an active medium in lasers.

Another object of the invention is to provide a perimidone dye whichemits laser light having an oscillation wavelength of 500 to 550 nm.

A further specific object of the invention is to provide a perimidonedye of formula (I) for use as an active medium in a laser emitting alight having an oscillation wavelength of 500 to 550 nm: ##STR2##wherein R¹ is a hydrogen atom, an alkyl group, a trifluoromethyl group,an alkoxycarbonyl group, an alkoxycarbonylalkyl group, an aralkyl groupor a phenyl group; R² is an optionally substituted alkoxycarbonyl group,a cyclohexyloxycarbonyl group, a tetrahydrofurfuryloxycarbonyl group, anaryloxycarbonyl group, a benzyloxycarbonyl group, an acyl group, a cyanogroup or an optionally substituted carbamoyl group; R³ and R⁴ which maybe the same or different are each a hydrogen atom, an alkyl group, analkoxyalkyl group, an aralkyl group or an aryl group.

These and other objects and advantages of the present invention willbecome apparent by reading the following description.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a dye laser, and more particularly to adye laser which uses a perimidone dye as the active medium for emittinglaser light having an oscillation wavelength of 500 to 550 nm.

The dye laser of the present invention uses a novel perimidone dye asthe active medium, and emits a laser light having an oscillationwavelength of 500 to 550 nm. This laser can be used in isotopeseparation, and is particularly suited for uranium enrichment.

A laser, a kind of light amplifier, is capable of producing amonochromatic coherent light having high intensity and directionality.Among the various types of lasers, dye lasers are well developed lasersin which the active medium is a liquid and their principal componentsare a transparent container for a solution of a dyestuff and an opticalresonator made of a pumping energy source optically coupled to thatcontainer. In order to avoid optical non-uniformity, the dye solution ofa given concentration is usually passed through the circulation systemcontaining the transparent container throughout the laser operation.

The pumping energy source emits light of high energy density necessaryfor operating the dye laser, and suitable sources include dischargetubes, flash lamps, gas lasers (e.g. N₂ and Ar lasers) and solid-statelasers (e.g. Nd-YAG laser). As a result of pumping, the dye molecule isexcited to an upper energy state to cause radiation transition. Theemitted light which propagates along the axis of the resonator isconfined there for a sufficient period of time to cause a stronginteraction with the excited dye molecule. If the number of the exciteddye molecules exceeds that of the molecules in the ground state,stimulated emission occurs and the light is amplified in the resonatorto produce an oscillating laser light.

One great advantage the dye laser has over solid-state lasers or gaslasers is that it can be operated with many kinds of organic dyesemitting fluorescent light at their own specific wavelengths whichoverlap to cover the entire visible spectrum. This brings about thepossibility of designing a dye laser capable of light emission at anydesired wavelength in the visible region. Another important feature ofthe dye laser is its tunability, i.e. the continuous adjustability ofthe output dye laser wavelength over a relative small region ofwavelengths.

According to the present invention, a dye laser having an oscillatingwavelength of 500 to 550 nm is provided, and it is characterized byusing as an active medium a novel perimidone dye of formula (I) havinghigh conversion efficiency: ##STR3## wherein R¹ is a hydrogen atom, analkyl group, a trifluoromethyl group, an alkoxycarbonyl group, analkoxycarbonylalkyl group, an aralkyl group or a phenyl group; R² is anoptionally substituted alkoxycarbonyl group, a cyclohexyloxycarbonylgroup, a tetrahydrofurfuryloxycarbonyl group, an aryloxycarbonyl group,a benzyloxycarbonyl group, an acyl group, a cyano group or an optionallysubstituted carbamoyl group; R³ and R⁴ which may be the same ordifferent are each a hydrogen atom, an alkyl group, an alkoxyalkylgroup, an aralkyl group or an aryl group.

Examples of the substituent represented by R¹ in formula (I) include ahydrogen atom, an alkyl group such as methyl, ethyl and propyl, butyl,hexyl or octyl; a trifluoromethyl group; an alkoxycarbonyl group such asmethoxycarbonyl, ethoxycarbonyl, propoxycarbonyl or butoxycarbonyl; analkoxycarbonylalkyl group such as methoxycarbonylmethyl,ethoxycarbonylmethyl, propoxycarbonylmethyl or butoxycarbonylmethyl; aphenyl group; and an aralkyl group such as benzyl or phenetyl. Examplesof R² include an alkoxycarbonyl group such as methoxycarbonyl,ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, hexyloxycarbonyl oroctyloxycarbonyl; an alkoxycarbonyl group substituted by alkoxy,alkoxyalkoxy or alkylamino, such as methoxyethoxycarbonyl,ethoxyethoxycarbonyl, propoxyethoxycarbonyl, butoxyethoxycarbonyl,methoxypropoxycarbonyl, methoxyethoxyethoxycarbonyl,ethoxyethoxyethoxycarbonyl, propoxyethoxyethoxycarbonyl,buthoxyethoxyethoxycarbonyl, dimethylaminoethoxycarbonyl ordiethylaminoethoxycarbonyl; a cyclohexyloxycarbonyl group; atetrahydrofurfuryloxycarbonyl group; a benzyloxycarbonyl group; anaryloxycarbonyl group such as tolyloxycarbonyl or phenoxycarbonyl; anacyl group such as acetyl, benzoyl or thienoyl; a cyano group; acarbamoyl group; and a substituted carbamoyl group such asphenylcarbamoyl, methylcarbamoyl, ethylcarbamoyl, propylcarbamoyl,butylcarbamoyl, dimethylcarbamoyl, diethylcarbamoyl ormorpholinocarbamoyl. Examples of the substituents represented by R³ andR⁴ include a hydrogen atom; an alkyl group such as methyl, ethyl, propylor butyl; an alkoxyalkyl group such as methoxyethyl, ethoxyethyl,methoxypropyl or ethoxypropyl; an aralkyl group such as benzyl orphenetyl; and an aryl group such as phenyl, p-methoxyphenyl, p-tolyl orp-chlorophenyl.

The perimidone dye of formula (I) may be produced by reacting a compoundof formula (II): ##STR4## (wherein R¹ and R² are the same as definedabove; X and Y which may be the same or different are each a halogenatom, an alkoxy group or an aryloxy group) with a urea of formula (III):

    R.sup.3 NH--CO--NHR.sup.4                                  (III)

(wherein R³ and R⁴ are the same as defined above).

For use in the dye laser of the present invention, the perimidone dye offormula (I) is formulated as a solution having a concentration of 10⁻¹to 10⁻⁴ mols per liter. Water and various organic solvents may be usedto form the solution. Suitable organic solvents include monovalentalcohols such as methanol, ethanol, isopropanol and butanol; polyvalentalcohols such as ethylene glycol; cellosolves such as methyl cellosolveand ethyl cellosolve; cyclic ethers such as tetrahydrofuran and dioxane;aromatic hydrocarbons such as benzene, toluene and xylene; phenols suchas phenol and resorcin; alicyclic hydrocarbons such as cyclohexane anddecalin; ketones such as acetone, butanone-2 and cyclohexanone; esterssuch as ethyl acetate, diethyl malonate, ethylene glycol diacetate anddiethyl carbonate; halogenoalkanes such as chloroform; fluoroalcoholssuch as fluoroisopropyl alcohol; sulfoxides such as dimethylsulfoxide;and N,N-dialkylcarboxylic acid amides such as N,N-dimethylformamide andN,N-dimethylacetamide.

The present invention is hereunder described by working examples whichare given here for illustrative purposes only and are by no meansintended to limit the scope of the invention.

EXAMPLE 1

A dye having the formula: ##STR5## was dissolved in dioxane at aconcentration of 1.0×10⁻² mol/liter. The solution was put into a quartzcell and the lasing characteristics of the dye were measured using aNd-YAG pump laser emitting a laser light of 355 nm (third harmonics).Such measurement can be effected with an apparatus including the Nd-YAGlaser, a dye laser proper, a monochromater, an oscilloscope, a powermeter, a YAG output monitor, and oscillator-associated beam spliter, atotal refecting mirror, a defraction grating, a quartz cell forcontaining the dye solution, and an output mirror. The maximumoscillating wavelength was 535 nm and the output was 4.8×10⁻⁴ J.

EXAMPLES 2 to 29

Solutions of the dyes listed in Table 1 were prepared (for the solventsand the concentrations of the dyes, also see Table 1). The results ofmeasurement of the oscillating wavelength are shown in Table 1.

    TABLE 1      ##STR6##       conc. max. oscillating Ex. No. R.sup.1 R.sup.2 R.sup.3 R.sup.4 Solvent (     mol/l) wavelength       2 CH.sub.3 COOCH.sub.3 CH.sub.3 CH.sub.3 dioxane 5 × 10.sup.-3     524 3 CH.sub.3 COOC.sub.4 H.sub.9.sup.(iso) C.sub.4 H.sub.9.sup.(n)     C.sub.4 H.sub.9.sup.(n) dioxane 5 × 10.sup.-2 532 4 CH.sub.3     COOC.sub.6 H.sub.13.sup.(n) C.sub.2 H.sub.5 C.sub.2 H.sub.5 dioxane 1.5     × 10.sup.2    588 5 CH.sub.3 COOC.sub.4 H.sub. 9.sup.(iso) C.sub.2     H.sub.5 C.sub.2 H.sub.5 N,Ndimethylformamide 8 × 10.sup.-3 526  6     CH.sub.3      ##STR7##      C.sub.2 H.sub.5 C.sub.2 H.sub.5 N,Ndimethylformamide 6 ×      10.sup.-3 519  7 CH.sub.3 H CH.sub.3 CH.sub.3 N,Ndimethylformamide 8     × 10.sup.-4 529      8     ##STR8##      ##STR9##      CH.sub.3 CH.sub.3 N,Ndimethylformamide 6 × 10.sup.-4 534  9     CH.sub.3 COO(CH.sub.2).sub.2 OC.sub.4 H.sub.9.sup.(n) CH.sub.3 CH.sub.3     dioxane 1 × 10.sup.-3 536 10 CF.sub.3 COOC.sub.2 H.sub.5 C.sub.4     H.sub.9.sup.(n) C.sub.4 H.sub.9.sup.(n) dioxane 3 × 10.sup.-3 526     11 CH.sub.3      ##STR10##      C.sub.3 H.sub.7.sup.(n) C.sub.3 H.sub.7.sup.(n) methyl ethyl ketone 4     × 10.sup. -3 525      12 CH.sub.3     ##STR11##      CH.sub.3 C.sub.4 H.sub.9.sup.(n) dioxane 4 × 10.sup.-2 541  13     COOCH.sub.3 COOCH.sub.3 C.sub.4 H.sub.9.sup.(n) C.sub.4 H.sub.9.sup.(n)     N,Ndimethylformamide 5 × 10.sup.-4 521      14 CH.sub.3     ##STR12##      C.sub.2 H.sub.5 C.sub.2 H.sub.5 dioxane 4 × 10.sup.-4 520  15     CF.sub.3      ##STR13##      CH.sub.3 CH.sub.3 dimethylsulfoxide 3 × 10.sup.-4 526  16     CH.sub.3      ##STR14##      H H dimethylsulfoxide 1 × 10.sup.-4 512  17 CF.sub.3 COCH.sub.3     CH.sub.3 C.sub.4 H.sub.9.sup.(n) dioxane 1 × 10.sup.-4 519  18     CH.sub.3      ##STR15##      CH.sub.3 CH.sub.3 dimethylsulfoxide 1 × 10.sup. -4 528  19      ##STR16##      COOC.sub.2 H.sub.5 C.sub.2 H.sub.4 OCH.sub.3 C.sub.2 H.sub.4 OCH.sub.3     dioxane 3 × 10.sup.-4 523      20     ##STR17##      COOC.sub.2      H.sub.5     ##STR18##      ##STR19##      chloroform 4 × 10.sup.-4 539      21     ##STR20##      ##STR21##      ##STR22##      ##STR23##      dioxane 3 × 10.sup.-3 582  22 CH.sub.3 CN C.sub.4 H.sub.9.sup.(n) C     .sub.4 H.sub.9.sup.(n) dioxane 4 × 10.sup.-2 530 23 CH.sub.3     COOCH.sub.2CHCH.sub.2 CH.sub.3 CH.sub.3 dioxane 3 × 10.sup.-4 517     24 C.sub.6      H.sub.13.sup.(n) COCH.sub.3 CH.sub.3 CH.sub.3 N,Ndimethylformamide 4     × 10.sup.-4 528 25 CH.sub.2COOCH.sub.3 COOCH.sub.3 C.sub.2 H.sub.5     C.sub.2 H.sub.5 N,Ndimethylformamide 3 × 10.sup.-4 526  26     CH.sub.3      ##STR24##      CH.sub.3 CH.sub.3 N,Ndimethylformamide 1 × 10.sup.-4 518  27     CH.sub.3      ##STR25##      CH.sub.5 C.sub.2 H.sub.5 N,Ndimethylformamide 2 × 10.sup.-4 524     28 CH.sub.3 CONHC.sub.2 H.sub.5 C.sub.2 H.sub.5 C.sub.2      H.sub.5 N,Ndimethylformamide 1 × 10.sup.-4 531  29 CH.sub.3      ##STR26##      CH.sub.3 C.sub.4 H.sub.9.sup.(n) N,Ndimethylformamide 2 ×     10.sup.-4 530  30 CH.sub.3 COOC.sub.6 H.sub.13.sup.(n) H C.sub.6     H.sub.13.sup.(n) N,Ndimethylformamide 1 × 10.sup.-4 528  31     CH.sub.3      ##STR27##      ##STR28##      ##STR29##      dioxane 3 ×      10.sup.-2 546

What is claimed is:
 1. A dye laser including a container for a dyesolution and a pumping energy source coupled thereto, said dye solutioncontaining a perimidone dye of formula (I): ##STR30## wherein R¹ is ahydrogen atom, an alkyl group, a trifluoromethyl group, analkoxycarbonyl group, an alkoxycarbonylalkyl group, an aralkyl group ora phenyl group; R² is an optionally substituted alkoxycarbonyl group, acyclohexyloxycarbonyl group, tetrahydrofurfuryloxycarbonyl group, anaryloxycarbonyl group, a benzyloxycarbonyl group, an acyl group, a cyanogroup or an optionally substituted carbamoyl group; R³ and R⁴ which maybe the same or different are each a hydrogen atom, an alkyl group, analkoxyalkyl group, an aralkyl group or an aryl group.
 2. A dye laseraccording to claim 1 wherein the dye solution contains 10³¹ 1 to 10⁻⁴mols of the perimidone dye per liter.
 3. A dye laser according to claim1 which has an oscillating wavelength range of 500 to 550 nm.
 4. A dyesolution for use in conjunction with a dye laser, said solutionconsisting essentially of a dye and a solvent therefore, said dye beingof the formula (I): ##STR31## wherein R¹ is a hydrogen atom, an alkylgroup, a trifluoromethyl group, an alkoxycarbonyl group, analkoxycarbonylalkl group, an aralkyl group or a phenyl group; R² is anoptionally substituted alkoxycarbonyl group, a cyclohexyloxycarbonylgroup, tetrahydrofurfuryloxycarbonyl group, an aryloxycarbonyl group, abenzyloxycarbonyl group, an acyl group, a cyano group or an optionallysubstituted carbamoyl group; R³ and R⁴ which may be the same ordifferent are each a hydrogen atom, an alkyl group, an alkoxyalkylgroup, an aralkyl group or an aryl group.
 5. A dye solution according toclaim 4 containing 10⁻¹ to 10⁻⁴ mols of the perimidone dye per liter.